Union leader John Dougherty announced yesterday that he will not run for mayor, saying he needed to devote himself to his ailing mother.

"I only get one mom," said Dougherty, business manager of IBEW Union Local 98, who had long been viewed as a likely candidate. "I wasn't about to sacrifice any of this quality time."

Dougherty declined to disclose details of his mother's illness but said she has been hospitalized for some time.

"If there's anything I'm upset about, I would have loved to have been in every neighborhood, every kitchen, every church and express my opinion," Dougherty said.

Armed with the electricians union's fundraising ability and powerful street army, Dougherty has flirted with running for years. Supporters formed a committee called Draft John Dougherty 2007, which raised money, hired airplanes to haul Dougherty banners over the Jersey Shore in the summer and gave out Dougherty Christmas ornaments during the holiday season.

But in recent months, Dougherty has kept a lower profile, perhaps in part because of a run of negative press.

Last spring, Dougherty was pushed out as treasurer of the city Democratic Party after a battle with party chairman (and now mayoral candidate) Bob Brady.

And federal authorities recently searched Dougherty's house in connection with an ongoing investigation of a contractor friend, Gus Dougherty, who is no relation.

Still, Dougherty said, he would have been competitive if he had run.

"I've got position papers on everything," he said.

Dougherty said that Brady, who plans to announce his candidacy tomorrow, had no bearing on the decision.

"Bob really didn't have any influence on my decision in running for mayor," he said, but "out of respect to Bob and the other candidates, I wanted to do this now."

Brady yesterday said he had heard that Dougherty had pulled out. He declined to comment.

Dougherty also insisted that the federal probe didn't derail him.

Dougherty did not say whom he might support in the mayor's race.

With his withdrawal, the major candidates remain Brady, state Rep. Dwight Evans, U.S. Rep. Chaka Fattah, millionaire Tom Knox and ex-City Councilman Michael Nutter.

For now, Dougherty plans to continue his work with Local 98 and his various charitable interests. But at 46, he could run in four years, or eight.

"I love Philly and I'm not going anyplace," Dougherty said. *